Monochromators are optical instruments used to separate monochromatic light from a wider range of wavelengths of light. To spatially separate colors or bands of broadband light, a monochromator can rely upon optical dispersion by way of a prism or diffraction by way of a diffraction grating. Grating monochromators can disperse broadband light over a certain range of wavelengths, such as ultraviolet, visible, or infrared, for example, using replica gratings.